58648-10-5Relevant academic research and scientific papers
Chiral phosphine ligand libraries based on the Bull–James three-component supramolecular assembly
Su, Hsin Y.,Gorelik, Daniel,Taylor, Mark S.
, p. 190 - 202 (2019)
An approach to the synthesis of libraries of chiral phosphine ligands is described, using condensations of 2-formylarylboronic acids, diols or related compounds, and aminophosphines. The three-component nature of this condensation, along with the ready av
π-Coordinating Chiral Primary Amine/Palladium Synergistic Catalysis for Asymmetric Allylic Alkylation
Chai, Junli,Luo, Sanzhong,Mi, Xueling,Wang, Yaning,You, Chang,Zhang, Jie,Zhang, Long
, p. 3184 - 3195 (2020)
We report an arene-containing chiral primary amine as a dual aminocatalyst and ligand: The π-coordinating aminocatalyst/palladium synergistic catalysis for asymmetric allylic alkylation of α-branched β-ketocarbonyls. The use of arene-containing chiral primary amine catalyst led to not only enhanced reaction rate but also reversed chiral induction compared with its sterically bulky derivative. Both enantiomers of the allylic adducts bearing acyclic all-carbon quaternary stereocenters could be obtained from the same configured chiral aminocatalysts with high efficiency and excellent regio-, stereo-, and enantioselectivity. Mechanistic studies revealed a distinctive Pd-arene π-coordination mode for effective catalysis. The π-coordinating chiral primary amine catalyst could be successfully applied in the asymmetric allylation reactions of vinylethylene carbonates, vinyl epoxides, or simple allylic alcohols.
Enantioselective Palladium-Catalyzed Decarboxylative Allylation of β-Keto Esters Assisted by a Thiourea
Qian, Hua,Gu, Guoxian,Zhou, Qinghai,Lu, Jiaxiang,Chung, Lung Wa,Zhang, Xumu
supporting information, p. 51 - 56 (2017/10/06)
Enantioselective intramolecular decarboxylative allylation of β-keto esters catalyzed by a palladium bis(phosphine)-thiourea complex is reported. This procedure is not only effective for β-keto esters, but also effective for β-keto amides. An intermolecular variant of the asymmetric decarboxylative allylation is also established. DFT calculations indicate that an outer-sphere mechanism is viable for the decarboxylative allylation of β-keto esters.
High-throughput screening of the asymmetric decarboxylative alkylation reaction of enolate-stabilized enol carbonates
McDougal, Nolan T.,Virgil, Scott C.,Stoltz, Brian M.
experimental part, p. 1712 - 1716 (2010/08/23)
The use of high-throughput screening allowed for the optimization of reaction conditions for the palladium-catalyzed asymmetric decarboxylative alkylation reaction of enolate-stabilized enol carbonates. Changing to a nonpolar reaction solvent and to an electron-deficient PHOX derivative as ligand from our standard reaction conditions improved the enantioselectivity for the alkylation of a ketal-protected,1,3-diketone-derived enol carbonate from 28% ee to 84% ee. Similar improvements in enantioselectivity were seen for a β-keto ester derived and an α-phenyl cyclohexanone-derived enol carbonate. Georg Thieme Verlag Stuttgart New York.
Catalytic enantioselective claisen rearrangements of O-allyl β-ketoesters
Uyeda, Christopher,Roetheli, Andreas R.,Jacobsen, Eric N.
supporting information; experimental part, p. 9753 - 9756 (2011/02/23)
A chiral guanidinium ion is shown to catalyze enantioselective Claisen rearrangements of O-allyl β-ketoesters in 78-87 % ee (see scheme). The pericyclic nature of the process allows products containing vicinal stereogenic centers to be accessed with both enantio- and diastereocontrol. Copyright
Enantioselective synthesis of spiro [4.4]non- and spiro[4.5]dec-2-ene-1,6-diones
Chitkul,Pinyopronpanich,Thebtaranonth,Thebtaranonth,Taylor
, p. 1099 - 1102 (2007/10/02)
Spiro[4.4]non- and spiro[4.5]dec-2-ene-1,6-diones [2; N = 0 and 1] were prepared in moderate to high enantiomeric purities via asymmetric allylation of enamines 6 and ketal derivatives 7 and 8 formed from keto-esters 5, followed by a carbanionic cyclization process.
Stereoselective reactions. XXI. Asymmetric alkylation of α-alkyl β-keto esters to α,α-dialkyl β-keto esters having either (R)- Or (S)-chiral quaternary center depending on the solvent system
Ando, Kaori,Takemasa, Yataka,Tomioka, Kiyoshi,Koga, Kenji
, p. 1579 - 1588 (2007/10/02)
Asymmetric alkylation reaction of chiral enamines prepared from α-alkyl β-keto esters and (S)-valine tert-butyl ester leading to either enantiomer is described. Lithiated chiral enamines can be alkylated with alkyl halides in a toluene solvent in the presence of HMPA to give, after hydrolysis, α,α-dialkyl β-keto esters in 70-99%ee. The reactions in the presence of THF, dioxolane, or trimethylamine, instead of HMPA, afford the corresponding antipodes with enantiomeric purities of 44-92%ee. The present method provides a procedure for the synthesis of both enantiomers of α,α-dialkyl β-keto esters in high enantiomeric purities starting from the same chiral enamines.
144. Ueber die Stereoselektivitaet der α-Alkylierung von (1R,2S)(+)-cis-2-Hydroxy-cyclohexancarbonsaeureaethylester
Frater, Gyoergy
, p. 1383 - 1390 (2007/10/02)
In continuation of our work on the stereoselectivity of the α-alkylation of β-hydroxyesters , we studied this reaction with the title compound (+)-2.The latter was prepared through reduction of 1 with baker's yeast.Alkylation of the dianion of (+)-
